Conventionally, a base station assigns a wireless channel to a mobile station. However, on this occasion, the channel has been assigned at random without considering a moving state of the mobile station. For the wireless channel assignment, “channel assignment scheme” (see Patent Document 1) and “spatial division multiple access wireless communication system and channel assignment method thereof” (see Patent Document 2) are known. For the above mentioned “channel assignment scheme”, a base station gives a priority to wireless channels and measures interference wave power of the wireless channels. Then the base station increases the priority if the interference wave power is less than a certain value and decreases the priority if the interference wave power is equal to or greater than the certain value, then determines the priority of the channels in order of priority and assigns the wireless channels to the mobile station.
For the above mentioned “spatial division multiple access wireless communication system and channel assignment method thereof”, a distance metric is calculated with respect to each pair of wireless communication apparatuses that shares a channel. Then, when the calculated distance metric satisfies a required index, a spatial channel is assigned to the wireless communication apparatuses. On the contrary, when the calculated distance metric, does not satisfy the required index, one of the wireless communication apparatuses is reassigned to a new channel, or handover is performed. Patent Document 1: Japanese Patent Application Laid-Open Publication No. 7-255078 Patent Document 2: Japanese Patent Application Laid-Open Publication No. 9-215052